#include<stdio.h>
#include<math.h>
int main()
{
	int n,i,k;
	do
	{
		printf("Enter a posotive integer :");
		scanf("%d",&n);
		
	}while(n<=0);
	if (n==1)
	printf("%d is not a prime.\n",n);
	
	else{
		k = (int)sqrt(n);
		for(i=2;i<=k;i++)
		{
			if(n%i==0)
			break;
		}
		if(i>k)
		printf("%d is a prime.\n",n);
		else{
			printf("%d is not a prime",n);
		}
	} 
	return 0;
    
	} 
